I building a new kart (yes, still building....LOL). It has been a PROJECT and a half. Anyway, the thing is getting a little porky. That makes me consider a set of duals. I would like to have 3 nearly identical engines so I can swap them as needed. I have a green head reedjet already. I'd really like 2 more of those BUT regular reedjets can make due....or 3 TT-75s.